1. Field of the Invention
The present invention relates to a concrete container for introducing concrete into formworks. The concrete container includes an upwardly open vessel with a downwardly narrowing bottom portion with an outlet opening and a flexible pipe, particularly a hose, connected to the outlet opening for distributing the concrete. The vessel and/or a support frame supporting the vessel include suspension means for suspending the concrete container from a lifting means. Underneath the outlet opening of the concrete container, an essentially horizontally extending crossbeam is arranged, wherein the crossbeam is arranged so as to be displaceable transversely of the freely suspended flexible pipe. The displacement distance of the crossbeam corresponds at least approximately to the diameter of the flexible pipe, wherein, when the crossbeam is displaced, the crossbeam traverses the area underneath the outlet opening and reduces the cross-section of the flexible pipe as a result.
2. Description of the Related Art
In civil engineering, concrete containers are used for filling formworks with concrete when erecting a structure. In the simplest embodiment, this concrete container has an outlet opening with a sliding valve which can be actuated by means of a pivotally mounted lever. The concrete container suspended from a lifting means is moved laterally against a concrete transporting vehicle and is filled with concrete through a chute. The concrete container filled in this manner is then lifted by the lifting means and is moved to the location where the concrete is to be introduced into the formwork. An operator placed at this location actuates the lever for opening the sliding valve and the concrete slides as a result of its own weight through the outlet opening into the formwork. After the concrete container has been emptied in this manner, the sliding valve is again closed by means of the afore-mentioned lever and the concrete container is subsequently returned by means of the lifting means to the concrete transporting vehicle, where the container is filled again. Concrete containers of this type have been found very useful in the case of those formworks in which the upper rim is freely accessible. This is usually the case in formworks as they are used in the construction of houses and apartment buildings.
However, the accessibility of the formwork is significantly impaired if the formwork is constructed as a sliding formwork, as it is preferably used when erecting tower-like structures. Such a formwork is shown, for example, in Austrian patent application A 634/91, published Jul. 15, 1992. In that case, the formworks or formwork sections are suspended from support yokes, which, as a rule, support work platforms on both sides of the structure to be erected and, of course, the formwork itself. Moreover, reinforcing iron members arranged closely next to each other protrude upwardly to a significant extent, as shown on the coversheet of "Beton- und Stahlbetonbau" concrete and reinforced concrete construction! Volume 10/92, 87th year.
Concrete containers of the above-described type are no longer capable of filling these sliding formworks because the various structures of the formworks make it impossible for the concrete container to be moved sufficiently close to the rim of the formwork. For this reason, concrete containers of this type have been equipped with a distributing hose, wherein a sliding valve is provided between the hose and the outlet opening of the container. In addition, a platform is attached to the support frame of the concrete container on which an operator is standing whose purpose it is to actuate the sliding valve, wherein a second operator guides the end of the hose, which is usually several meters long, to the filling area of the formwork. Upon instructions by the second operator, the operator on the support platform actuates the sliding valve. Since the use of a sliding formwork for erecting a structure requires that concrete is filled into the formwork continuously, it is necessary that an operator is transported together with this concrete container at all times, wherein the only task of this operator is to open and close the sliding valve upon command of another operator. This manner of operation is not particularly economical.
In order to avoid these problems, in accordance with another development, the sliding valve has been mounted at the outlet end of the distributing hose, so that the operator who guides the hose also operates the sliding valve. In order to ensure that the distributing hoses can reach the formwork rim, they usually have a length of 6 to 7 m and a diameter of about 20 cm. In operation, the distributing hose is fully filled with concrete and, therefore, the distributing hose is very heavy, so that usually two operators are required for handling the end of the distributing hose equipped with the sliding valve. In addition, under the rough conditions as they exist on a construction site, the protruding reinforcing steel members may damage and rip open the distributing hose, which would mean that, in the case of a full concrete container, the contents thereof would drop onto persons standing underneath the concrete container. The contents of the concrete container have a weight of several tons.
In order to overcome this disadvantage, it has been provided in a further development of the construction described above, to provide a pipe piece between the outlet opening of the container and the distributing hose. A motor-driven screw is mounted in this pipe piece. The motor for driving the screw is attached to the container or the support frame for the container. The axial length of the screw is slightly greater than axial length of the pipe piece. Fastened to the upper rim of the container is a crossbeam located in the diameter plane of the container, wherein the motor for the screw is flanged to the middle portion of the crossbeam. The drive shaft extends concentrically through the container. The pipe piece is alignment with the vertical center axis of the container. In this construction known from AT 399 010 B, the flow of the concrete out of the container is controlled by means of the screw. However, this requires that the concrete has a sufficiently firm consistency. If a relatively liquid concrete is being processed, the screw is not sufficient for holding this thin, flowable concrete back reliably.
In order to overcome this disadvantage, it has already been proposed in DD 146 985 A to arrange a closing mechanism underneath the outlet opening. This closing mechanism is composed of elastic sealing members arranged at the longitudinal sides of the outlet opening and an elastic closing sheet stretched from one narrow side to the other narrow side of the opening, wherein the closing sheet is attached to one narrow side and to a roller. The roller has on both sides thereof gears connected to drive shafts, wherein hand wheels are mounted on the drive shafts. The gears engage in racks, wherein compressive rack springs are mounted in the extensions of the racks. These compressive rack springs are arranged in bearing rails, wherein rollers are arranged in the bearing rails underneath the racks. The bearing rails rest on compressive bearing rail springs in the housing, wherein the compressive bearing rail springs are fastened to the middle stiffening plane of the frame. A funnel with the hose is located underneath the closing mechanism. This closing mechanism is not only of complicated construction, it is also susceptible to trouble to a significant extent because the gears and racks constitute an open gear system which very easily becomes dirty and is blocked under the conditions existing at a construction site.
A mouthpiece for ejecting viscous material disclosed in DE 33 10 176 A1 should also be mentioned in this connection. The mouthpiece includes a contraction valve with a controllable valve body of an elastic material. The mouthpiece includes two pipes of about equal size extending in a common longitudinal direction and a hose of an elastically deformable material for connecting the pipes, wherein the hose can be compressed between the two pipes. An outer pipe is sealingly connected to the two inner pipes by means of funnel-shaped components extending axially relative to the pipes, so that an annular space is created which can be connected to a pressure medium source. A mouthpiece of this type has a significant structural length and, therefore, is not suitable for concrete containers for the reasons already mentioned above.
Finally, the closing mechanism known from FR 2 359 262 A1 must be mentioned. In that case, pairs of spaced-apart tooth segments are arranged underneath the outlet opening of the container, wherein the tooth segments of each pair mesh with each other and one of the pairs can be swung by means of a lever. Several crossbeams can be arranged between the pairs of toothed segments, wherein the center points of the crossbeams are connected on a spiral line. The flexible hose attached to the outlet opening extends between the crossbeams. The hose can be squeezed closed by swinging the toothed segments. This device is of complicated construction and uses a lot of space; in addition, the tooth segments are structural components which are not advantageous under the rough conditions existing at a construction site.